Land reformer Tasso Azevedo describes how the MapBiomas Network turns decades of satellite imagery into detailed, legally robust land-use maps to expose and curb deforestation in Brazil and other tropical regions. By integrating high-resolution imagery, property registries, and protected area data, the project has dramatically increased enforcement against illegal deforestation, redirected finance away from destructive operations, and supported a wide range of environmental and social applications. The talk also highlights successful action against illegal gold mining and outlines plans to expand this collaborative mapping approach to cover most of the world's tropical forests.